The effects of the false vocal folds on laryngeal pressures and flows

As a laryngeal constriction, the false vocal fold (FVF) gap (the distance between the medial edges of the FVFs) may create important effects on phonation by altering the pressures within and flows through the larynx. The computational code FLUENT was used to examine the effects on pressures and flows for FVF gaps ranging from 0.02 to 2.06 cm, for three glottal angles (uniform and convergent/divergent 40 deg) and two minimal glottal diameters (0.04 and 0.06 cm), for constant subglottal pressure (8 cm H2O). The specific design of the FVFs followed prior literature. Results suggest three important ranges of FVF gaps: (1) when the FVF gap was 1.5–2 times the minimal glottal diameter, pressures were lower throughout the larynx, and flows were higher through the larynx (less flow resistance); (2) for smaller FVF gaps, intralaryngeal pressures increased and flows decreased; (3) for greater FVF gaps, pressures and flows were unaffected. Also, (4) the divergent glottal angle gave the greatest flows, (5) flow separ...